Planting Onion Bulbs in Fall – 5 Reasons to Grow

More than 80 percent of Americans use Onions as staple food. So, relying just on Spring harvest isn’t a good option.

Apart from spring, you can plant onion bulbs in the fall to keep your backyard productive throughout the year.

Depending on climatic conditions in your region, it is easy to grow onions from seeds or sets.

Fall is regarded as an ideal time to plant onion bulbs because the soil holds the warmth of summer, which allows the bulbs to establish roots.

And days are shorter with mild temperature that reduce bolting and pests.

Planting onions in fall allows extended growing season, resulting in larger and healthier bulbs in spring or early summer.

Before starting it is essential to choose the best onion variety, know growing requirements of the plant and prepare the soil for planting.

Know the Basics of Growing Onions

Growing onions is quite straightforward, but choosing the right variety and following some basics can make your harvest much better.

Onions prefers full sun and loose, fertile soil enriched with organic matter, ideally with a pH between 6.0 and 7.0.

They need steady watering, but the soil should drain well to prevent rot and disease. Avoid planting in heavy clay soils, as they restrict bulb growth and make it harder for onions to thrive.

Day length is the key factor when it comes to onion success.

Onions are classified into short-day, intermediate-day (day-neutral), and long-day types.

Southern states, like Texas and Georgia, are best suited for short-day onions such as Texas Early Grano or Yellow Granex (the famous Vidalia onion).

In central regions, day-neutral varieties like Candy and Red Burgundy perform well, while northern states do best with long-day onions like Walla Walla, Yellow Sweet Spanish, and Copra.

Planting time varies by region, but generally, onions go into the ground in early spring as soon as the soil can be worked, or in fall in milder southern areas. Starting with sets, transplants, or seeds all work, but preparing beds with compost or aged manure before planting gives the best results.

Also Read: 19 Vegetables to Plant in Fall

5 Reasons Why You Should Plant Onions in Fall

Starting early in the fall will extend the growing period and you can expect the harvest in spring. Else, you may have to wait until later summer for onion planted in spring.

This way you can keep your garden active year-round.

1. Strong Root Development Before Winter

Fall planting takes advantage of lingering soil warmth after summer. Even though the air is cooler, the soil stays warmer for longer, which is ideal for onions to grow strong roots. These roots anchor the plants and allow them to absorb nutrients and moisture over winter.

When onions go into dormancy during the coldest months, their well-established roots keep them stable and ready to grow vigorously once spring warmth returns.

Think of fall planting as giving your onions a head start that spring-planted onions simply don’t get.

2. Earlier Harvest in Spring or Summer

One of the biggest perks of fall planting is that onions wake up as soon as temperatures rise in spring.

Since they already have established roots, they start growing right away, unlike spring-planted onions that need time to get established first. This means you can harvest your onions earlier—sometimes up to a month sooner than usual.

Early harvests are especially handy if you want fresh onions before summer crops start filling your kitchen, or if you like to rotate crops and free up garden space for tomatoes, beans, or squash.

3. Bigger, Healthier Bulbs with Better Storage

Fall-planted onions usually grow larger bulbs because they enjoy a longer growing season overall.

Instead of being rushed to mature during late spring and summer heat, they have months of cool-season growth to slowly build size and strength. This gradual growth often leads to firmer, denser bulbs with excellent flavor and long storage life.

Many gardeners notice that fall-grown onions store better through the year compared to those planted in spring, which can sprout or spoil sooner.

4. Lower Risk of Bolting (Flowering Too Soon)

Bolting—when onions send up flower stalks—is a common frustration for gardeners. It usually happens when onions experience stress, like sudden swings between cold and warm weather in spring.

Once an onion bolts, bulb development stops, and the harvest becomes less usable. Planting in fall reduces this risk.

Since the plants establish themselves before the harsh shifts of spring weather, they’re less stressed and more focused on forming bulbs rather than flowering. This results in healthier onions and fewer disappointments.

5. Better Use of Garden Space Year-Round

Onions planted in fall are low-maintenance through winter. They grow slowly during the colder months, needing little attention, and by late spring or early summer, they’re ready to harvest. This timing is perfect because it frees up valuable garden space just when you need it for warm-season crops.

By planting onions in fall, you essentially stagger your garden’s productivity, ensuring you’re always harvesting something and keeping your beds in continuous use.

It’s a smart way to maximize both time and space in your garden.

Planting Onion Bulbs in Fall – Ultimate Guide

As mentioned earlier, planting onion bulbs in the fall allows to establish strong roots, survive the winter, and grow bigger, sweeter bulbs for an earlier harvest.

Choose the right variety for your region, plant 4–6 weeks before frost, and you’ll be rewarded with fresh green onions in spring and full-sized bulbs by early summer.

You can grow onions from sets or bulbs or start from seeds.

But, in later you must start germinating seeds indoors 8 weeks prior to planting outdoors.

1. Best Onions for Fall Planting

Not all onions are suited for fall planting. The success of your crop depends heavily on day length and climate.

• Short-Day Onions (Best for the South): These start bulbing with only 10–12 hours of daylight, making them ideal for regions like Texas, Georgia, Florida, and Southern California. Popular choices: Texas Early Grano, Yellow Granex (Vidalia type), and Red Creole.
• Intermediate or Day-Neutral Onions (Great for Central States): These need 12–14 hours of daylight and perform well in much of the middle U.S. Varieties like Candy, Red Burgundy, and Super Star are widely grown.
• Long-Day Onions (For Northern States): These require 14–16 hours of daylight and don’t do well with fall planting because of harsh winters. Northern gardeners should wait until spring to plant varieties like Walla Walla, Yellow Sweet Spanish, and Copra.

Check this: 19 Vegetables for Your Winter Garden

2. Preparing the Soil

Onions thrive in full sun and loose, well-drained soil. Preparing your soil well in fall ensures strong, healthy growth later.

• Soil type: Aim for sandy loam or raised beds for good drainage. Avoid heavy clay, which can suffocate bulbs and cause rot.
• Fertility: Mix in compost or well-rotted manure before planting. Onions are heavy feeders and appreciate nutrient-rich soil.
• pH range: Keep it slightly acidic to neutral (6.0–7.0).
• Weed-free start: Onions don’t compete well with weeds, so clear the bed thoroughly before planting.

3. How to Plant Onion Bulbs?

Planting onion sets is the most straightforward method for beginners. These are small, immature onion bulbs that regrow when replanted.

• Timing: Plant onion sets 4–6 weeks before your first expected hard frost. In most southern states, this means late September through November.
• Depth: Place each bulb about 1 inch deep with the pointed end facing upward.
• Spacing: Set them 4–6 inches apart in rows 12–18 inches apart. Closer spacing produces smaller onions (great for green onions), while wider spacing grows large storage bulbs.
• Watering: After planting, water well to settle the soil. Keep the soil evenly moist but not soggy.
• Mulching: Add a thin mulch layer of straw or shredded leaves to protect bulbs through winter.

4. Caring for Onions Through Winter

Onions are hardy and require little attention once planted. During winter, they grow slowly above ground while roots continue to develop.

• In mild climates, onions survive unprotected.
• In colder areas, add a heavier mulch to insulate against freezes. Remove it in early spring so sunlight warms the soil.
• Keep beds free of weeds, as onions can be easily crowded out.

5. Spring Growth and Harvest

When days lengthen and temperatures rise in early spring, onions shift into active growth.

• Watering: Keep the soil consistently moist during this stage to support bulb formation.
• Fertilizing: Side-dress with a nitrogen-rich fertilizer (like fish emulsion or compost tea) every few weeks until bulbs begin to swell.
• Harvesting green onions: You can start pulling young onions (scallions) as early as March in many southern regions.
• Harvesting mature bulbs: Most fall-planted onions are ready by late spring to early summer. They’re mature when the tops yellow and fall over naturally. Pull the bulbs and cure them in a dry, airy place before storage.

6. Growing Onions from Seeds

If you prefer to start from scratch, onions can also be grown from seeds. While slower, seeds offer a wider choice of varieties and often healthier plants.

• When to start seeds indoors: Sow seeds 8–10 weeks before your outdoor planting date. For fall planting in southern states, this means starting seeds indoors in July or August.
• Transplanting: Once seedlings are pencil-thin (about 6–8 inches tall), harden them off and plant them outdoors in fall.
• Direct sowing outdoors: In very mild climates, you can sow seeds directly in September for a spring harvest. Thin seedlings so they stand 4–6 inches apart.

7. When to Expect Your Harvest

Fall-planted onions give you a head start on spring harvests:

• Green onions (scallions): Ready in early spring.
• Full bulbs: Usually ready by late spring to early summer, depending on your region and variety. For example, onions planted in October in Texas or Georgia can often be harvested by May or June.

Also Read: 30 Best Vegetables to Grow in Containers

Conclusion

Fall is the second season for gardening.

You can plant onion bulbs or grow them from seeds. Fall planting allows extended growing period and healthy yield.

Choose the right variety and provide suitable growing conditions to successfully grow onions in your backyard.